I think the new Kanye West album is a good example of somebody really trying to do something new with it. Intentionally using the jarring, slightly inhuman vocals to create a sense of distance and isolation, something the album was intended to convey. Sort of an "uncanny valley" of voice. IMO, the song "Love Lockdown" is an excellent example of him really trying to make the autotuner into an instrument, and not just a tool. Now, the entire album is far from perfect, but I give him extra artist points for reach extending his grasp.
On the other hand, other pop songs use it horribly, and in such a way that it ruins the song. A good example there is the song "Nine in the Afternoon" by Panic! at the Disco. That song is supposed to have a warmth, and a little bit of a rough feel about it. It seems to have been written for a teenager in their room in a hormonal storm. And yet, the autotune, especially in the chorus, destroys that sense. It pulls you out of that feeling, and reminds you that it's not really the singers voice. Suddenly, he's not singing something you can commiserate with, he's singing words on a page.
I have a theory that it's impossible to prove anything, but I can't prove it.